Taxi and ambulance drivers show lower Alzheimer’s risk

By Dr. Priyom Bose, Ph.D.Reviewed by Benedette Cuffari, M.Sc.Jan 1 2025

Could navigating city streets and emergencies offer protection against Alzheimer’s? A groundbreaking study uncovers lower AD-related mortality in professions with high spatial demands.

Study: Alzheimer’s disease mortality among taxi and ambulance drivers: population based cross sectional study. Image Credit: WR7 / Shutterstock.com

A recent BMJ study analyzes Alzheimer’s disease (AD)-related mortality among taxi and ambulance drivers, both of which are occupations that require frequent spatial and navigational processing.

The hippocampus and AD progression

Deaths attributed to AD have doubled over the past thirty years and are expected to increase as the population ages. Despite the rising prevalence and morbidity associated with AD, there remains a lack of effective treatment and prevention strategies.

Previous research has indicated that taxi drivers in London exhibit enhanced functional changes in the hippocampus, a region of the brain that is responsible for episodic memory and learning. The hippocampus is often one of the first areas of the brain that is damaged in AD; therefore, it is worth investigating the risk of AD in individuals with certain occupations that require frequent spatial processing, such as taxi and ambulance drivers.

About the study

The current study assessed AD-related mortality among taxi and ambulance drivers utilizing population-based United States mortality data. The operating hypothesis was that occupations that demand frequent real-time spatial and navigational processing could be associated with a lower AD burden than other occupations.

Mortality data for deceased adults were obtained from the National Vital Statistics System from January 1, 2020, through December 31, 2022. The data included 443 occupational groups; however, the researchers were primarily interested in examining data on ambulance and taxi drivers, occupations involving extensive, unpredictable daily navigation.

For a more specific comparison group, aircraft pilots, bus drivers, and ship captains were considered. The primary outcome variable was the percentage of deaths for each occupation with AD as the underlying cause of death.

Study findings

A total of 8,972,221 people who died were identified, all of whom provided occupational information. The lowest average age at death among ambulance and taxi drivers was 64.2 years and 67.8 years, respectively.

Mainly, men were employed in these occupations except bus drivers, which was associated with a more equivalent representation of men and women. Aircraft pilots had a higher education level, whereas other navigational occupations more frequently reported high school education or less.

Of all study participants, nearly 4% were identified to have AD as the underlying cause of death. The unadjusted proportion of AD-related deaths was 1.03% and 0.74% among taxi and ambulance drivers, respectively, as compared to 3.11%, 4.57%, and 2.79% for bus drivers, pilots, and ship captains, respectively. With a similar average age at death, AD-related deaths were lower among taxi and ambulance drivers as compared to other occupations.

The two occupations with the lowest adjusted percentage of AD-related were taxi and ambulance drivers at 1.03% and 0.91%, respectively. In the general population, the adjusted percentage of deaths from AD was 1.69%. The adjusted odds ratio of death from AD was lowest among ambulance and taxi drivers as compared to those of other occupations.

Sensitivity analyses were conducted by restricting the sample to individuals who died at the age of 60 years or older and when AD was mentioned as an underlying or contributing cause of death. In these analyses, taxi and ambulance drivers had the lowest proportional AD mortality.

Other transportation-related occupations with fewer navigational demands did not exhibit a pattern of lower AD mortality. Out of 443 occupations, bus drivers, ship captains, and pilots ranked 263^rd, 23^rd, and fourth for adjusted AD mortality.

When vascular and unspecified dementia were considered, the pattern of low AD mortality among taxi and ambulance drivers was absent. This observation suggests the role of the hippocampus in taxi and ambulance drivers in lowering the risk of AD.

Conclusions

The study findings provide new insights into the potential relationship between taxi and ambulance driving and AD-related mortality. Nevertheless, additional research is needed to explore whether specific occupations requiring spatial cognitive work influence AD risk and if any cognitive activities can prevent AD.

Aside from the absence of a causal link, another key limitation of the current study is sample selection bias. Individuals at a high risk of developing AD are less likely to remain in the main occupations considered. The current study may also have underestimated the number of deaths caused by AD in death certificates.